Rate limiting is a crucial feature in NGINX that helps control the rate of requests sent to your server. This can prevent abuse, ensure fair usage, and protect your server from being overwhelmed by too many requests in a short period. In this section, we will cover the basics of rate limiting, how to configure it, and provide practical examples and exercises.
Key Concepts
- Rate Limiting Zones: Define shared memory zones to store the state of rate limiting.
- Limit Request Module: The module used to configure rate limiting in NGINX.
- Burst: Allows a temporary surge of requests beyond the defined rate.
- Delay: Introduces a delay for requests that exceed the rate limit but are within the burst limit.
Configuring Rate Limiting
Step 1: Define a Rate Limiting Zone
First, you need to define a shared memory zone to store the state of rate limiting. This is done using the limit_req_zone directive.
$binary_remote_addr: The variable used to identify the client (IP address).zone=one:10m: Defines a shared memory zone named "one" with 10MB of storage.rate=1r/s: Limits the rate to 1 request per second.
Step 2: Apply Rate Limiting to a Location
Next, apply the rate limiting to a specific location using the limit_req directive.
zone=one: Refers to the previously defined rate limiting zone.burst=5: Allows up to 5 requests to be queued beyond the rate limit.nodelay: Ensures that requests exceeding the rate limit are immediately rejected.
Example Configuration
Here is a complete example of an NGINX configuration with rate limiting:
http {
limit_req_zone $binary_remote_addr zone=one:10m rate=1r/s;
server {
listen 80;
server_name example.com;
location / {
limit_req zone=one burst=5 nodelay;
proxy_pass http://backend;
}
}
}Explanation
- The
limit_req_zonedirective creates a shared memory zone named "one" with a rate limit of 1 request per second. - The
limit_reqdirective in thelocation /block applies this rate limit to all requests to the root URL, allowing a burst of up to 5 requests.
Practical Exercises
Exercise 1: Basic Rate Limiting
Task: Configure NGINX to limit requests to 2 requests per second with a burst of 3 for the /api endpoint.
Solution:
http {
limit_req_zone $binary_remote_addr zone=api_zone:10m rate=2r/s;
server {
listen 80;
server_name example.com;
location /api {
limit_req zone=api_zone burst=3 nodelay;
proxy_pass http://backend_api;
}
}
}Exercise 2: Rate Limiting with Delay
Task: Configure NGINX to limit requests to 1 request per second with a burst of 5 and introduce a delay for requests exceeding the rate limit.
Solution:
http {
limit_req_zone $binary_remote_addr zone=delayed_zone:10m rate=1r/s;
server {
listen 80;
server_name example.com;
location / {
limit_req zone=delayed_zone burst=5;
proxy_pass http://backend;
}
}
}Common Mistakes and Tips
-
Mistake: Not defining a shared memory zone.
- Tip: Always ensure you have a
limit_req_zonedirective in thehttpblock.
- Tip: Always ensure you have a
-
Mistake: Misconfiguring the rate limit.
- Tip: Double-check the rate and burst values to ensure they meet your requirements.
-
Mistake: Forgetting to apply the rate limit to a specific location.
- Tip: Use the
limit_reqdirective within the appropriatelocationblock.
- Tip: Use the
Conclusion
In this section, we covered the basics of rate limiting in NGINX, including how to define rate limiting zones and apply them to specific locations. We also provided practical examples and exercises to help you understand and implement rate limiting effectively. Rate limiting is a powerful tool to protect your server from abuse and ensure fair usage among clients. In the next section, we will explore SSL/TLS configuration to secure your NGINX server.